Scour Critical Bridges

23,522 bridges across the US at risk from water erosion around foundations.

Scour Critical Bridges

Scour is the erosion of soil and rock around a bridge's foundation caused by moving water. When foundations are exposed or undermined, a bridge can collapse even if its deck and superstructure are in good condition. Scour is the leading cause of bridge failures in the US. These 23,522 bridges have been identified as vulnerable to scour damage.

Bridge State Scour Status Condition Year Built ADT
MILL RIVER Connecticut Scour Critical — Countermeasures Installed Poor 1935 6,505
NORTH CHICKAMAUGA CREEK Tennessee Scour Critical — Countermeasures Installed Good 1983 6,505
GUM CREEK Georgia Scour Critical — Countermeasures Installed Good 1990 6,502
S FORK SNOQUALMIE RIVER Washington Scour Critical — Countermeasures Installed Fair 1941 6,500
ONION RIVER Wisconsin Scour Critical — Countermeasures Installed Good 1961 6,500
GUNNISON RIVER Colorado Scour Critical — Countermeasures Installed Fair 1966 6,500
CERRO GORDO CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1960 6,500
PROVIDENCE RIVER Rhode Island Scour Critical — Countermeasures Installed Poor 1996 6,500
SMITH RIV SOUTH BANK RD California Scour Critical — Countermeasures Installed Fair 1940 6,500
CRUZ CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1942 6,500
CA%AS RIVER Puerto Rico Scour Critical — Countermeasures Installed Fair 1947 6,500
SECRET RAVINE California Scour Critical — Countermeasures Installed Fair 1929 6,490
SANDY RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1930 6,481
COLE CREEK Texas Scour Critical — Countermeasures Installed Fair 1965 6,480
MILL BROOK New Hampshire Scour Critical — Countermeasures Installed Fair 1928 6,478
SKULLS CREEK Louisiana Scour Critical — Countermeasures Installed Poor 1954 6,478
TANG RIVER RELIEF Louisiana Scour Critical — Countermeasures Installed Fair 1955 6,478
TANGIPAHOA RIVER RELIEF Louisiana Scour Critical — Countermeasures Installed Good 1986 6,478
SHELL HARBOR CANAL Florida Scour Critical — Countermeasures Installed Fair 1969 6,470
DEER CREEK Oregon Scour Critical — Countermeasures Installed Fair 1950 6,466
MILTON CREEK Oregon Scour Critical — Countermeasures Installed Fair 1958 6,466
OVERFLOW CHANNEL Oregon Scour Critical — Countermeasures Installed Fair 1970 6,459
WISSAHICKON CREEK Pennsylvania Scour Critical — Countermeasures Installed Fair 1841 6,457
Tacony Creek Pennsylvania Scour Critical — Countermeasures Installed Poor 1914 6,455
SKEEBO BRANCH South Carolina Scour Critical — Countermeasures Installed Fair 1958 6,450
TUALATIN RIVER Oregon Scour Critical — Countermeasures Installed Fair 1971 6,446
ROCKAWAY RIVER New Jersey Scour Critical — Countermeasures Installed Fair 1910 6,446
HAW CREEK Indiana Scour Critical — Countermeasures Installed Fair 1930 6,443
STREAM Washington Scour Critical — Countermeasures Installed Fair 1937 6,441
OUTLET BROOK New York Scour Critical — Countermeasures Installed Poor 1984 6,437
DRAIN Louisiana Scour Critical — Countermeasures Installed Fair 1939 6,435
DRAIN Louisiana Scour Critical — Countermeasures Installed Fair 1939 6,435
TANGIPAHOA RIVER Louisiana Scour Critical — Countermeasures Installed Poor 1939 6,435
OVER DUTCHMAN RUN Pennsylvania Scour Critical — Countermeasures Installed Fair 1947 6,433
OVER DUTCHMANS RUN Pennsylvania Scour Critical — Countermeasures Installed Poor 1948 6,433
HONEY CREEK Indiana Scour Critical — Countermeasures Installed Fair 1974 6,433
TIJERAS CANYON New Mexico Scour Critical — Countermeasures Installed Fair 1968 6,431
LONG TOM RIVER Oregon Scour Critical — Countermeasures Installed Fair 1963 6,426
MILL CREEK Indiana Scour Critical — Countermeasures Installed Good 1990 6,424
47 MILE CREEK Michigan Scour Critical — Countermeasures Installed Fair 1931 6,417
WILSON CREEK Michigan Scour Critical — Countermeasures Installed Fair 1931 6,417
WYLIE RUN Pennsylvania Scour Critical — Countermeasures Installed Poor 1905 6,411
S FK SKYKOMISH RIVER Washington Scour Critical — Countermeasures Installed Poor 1933 6,408
SOUHEGAN RIVER New Hampshire Scour Critical — Countermeasures Installed Fair 1917 6,406
CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1950 6,400
LOCUST CREEK Arkansas Scour Critical — Countermeasures Installed Fair 1947 6,400
HONDA CREEK Puerto Rico Scour Critical — Countermeasures Installed Poor 1891 6,400
HONDA CREEK Puerto Rico Scour Critical — Countermeasures Installed Fair 1891 6,400
SAGER CREEK Arkansas Scour Critical — Countermeasures Installed Fair 1985 6,400
WHITAKER CREEK Florida Scour Critical — Countermeasures Installed Good 1959 6,400

Scour Critical Bridges by State

States ranked by number of scour critical bridges.

StateScour CriticalUnaddressedCountermeasuresIneffective
Texas 3,912 75 516 3,321
Pennsylvania 2,233 45 2,187 1
Louisiana 1,302 13 1,288 1
South Carolina 1,263 0 1,217 46
Oregon 1,231 4 1,221 6
Michigan 1,081 14 1,062 5
Nebraska 962 224 732 6
New York 864 9 780 75
Indiana 756 7 749 0
Wisconsin 751 0 748 3
Kansas 638 9 626 3
California 623 27 562 34
Tennessee 581 12 569 0
Washington 516 14 487 15
Puerto Rico 496 9 487 0
Alabama 450 1 423 26
Iowa 392 3 385 4
New Jersey 362 2 360 0
Florida 357 4 339 14
Oklahoma 317 33 283 1
Missouri 312 4 307 1
Mississippi 301 6 286 9
Connecticut 279 0 276 3
Minnesota 257 38 202 17
Vermont 242 0 240 2
Colorado 241 3 238 0
Idaho 215 18 186 11
South Dakota 207 3 203 1
Arkansas 187 3 129 55
Massachusetts 166 15 106 45
Montana 166 13 140 13
Arizona 164 2 160 2
West Virginia 160 2 98 60
Alaska 159 1 146 12
Maine 140 13 126 1
North Carolina 130 9 105 16
New Mexico 127 4 114 9
North Dakota 102 14 87 1
Utah 100 6 82 12
Georgia 99 1 81 17
Illinois 99 3 85 11
Nevada 94 0 85 9
Rhode Island 94 0 93 1
New Hampshire 86 2 78 6
Hawaii 83 0 82 1
Kentucky 56 16 39 1
Maryland 54 1 51 2
Wyoming 51 1 48 2
Delaware 39 0 39 0
Ohio 12 2 4 6
Virginia 8 0 8 0
District of Columbia 5 0 4 1

Scour Critical Rating Codes

Code 2 — UnaddressedBridge is scour critical with no countermeasures installed. The foundation is vulnerable and no protective action has been taken.
Code 3 — Countermeasures InstalledProtective measures (riprap, sheet piling, etc.) have been installed to reduce scour risk, but the bridge remains classified as scour critical.
Code 6 — Countermeasures IneffectiveProtective measures were installed but have been assessed as ineffective. The bridge requires re-evaluation and additional action.

About Scour Critical Bridges

Scour critical bridges have been identified through underwater inspection or analysis as having foundations that are unstable or could become unstable during flood conditions. FHWA requires action plans for all scour critical bridges. Famous scour failures include the 1987 Schoharie Creek Bridge collapse in New York.